<template>
    <div class="todo-footer">
        <label>
            <input type="checkbox" v-model="isCheckAll">
        </label>
        <span><span>已完成{{ count }}</span>/全部 {{ todos.length }}</span>
        <button class="btn btn-danger" @click="clearAllCompletedTodos">清除已完成的任务</button>
    </div>
</template>

<script lang="ts">
import Todo from '@/types/todo'
import { computed, defineComponent } from 'vue'

export default defineComponent({
    name: 'Footer',
    props: {
        todos: {
            type: Array as () => Todo[],
            required: true
        },
        checkAll: {
            type: Function,
            required: true
        },
        clearAllCompletedTodos: {
            type: Function,
            required: true
        }
    },
    setup(props) {

        const count = computed(() => {
            return props.todos.reduce((pre, todo, index) => pre + (todo.isCompleted ? 1 : 0), 0)
        })


        const isCheckAll = computed({
            get() {
                return count.value > 0 && props.todos.length === count.value
            },
            set(val) {
                props.checkAll(val)
            }
        })

        return {
            count,
            isCheckAll
        }
    },
})
</script>


<style scoped>
.todo-footer {
    height: 40px;
    line-height: 40px;
    padding-left: 6px;
    margin-top: 5px;
}

.todo-footer label {
    display: inline-block;
    margin-right: 20px;
    cursor: pointer;
}

.todo-footer label input {
    position: relative;
    top: -1px;
    vertical-align: middle;
    margin-right: 5px;
}

.todo-footer button {
    float: right;
    margin-top: 5px;
}
</style>